In packet based networks, data packets are transported using a plurality of network routers. A router can receive a packet, analyze the packet's content, and forward the packet to the next hop or router using a routing algorithm based on the packet's content. For instance, in Multiprotocol Label Switching (MPLS) networks, the router can assign a plurality of Forwarding Equivalence Classes (FECs) to a plurality of packet types and associate each FEC with one next hop. As such, all packets that belong to a specific FEC are forwarded to the same next hop and hence can follow the same path or route in the network. The FECs can be assigned to the packet types once, for instance at the ingress node or first router in the network. The FEC can then be encoded as a short fixed length value known as a “label” and added to the packet. At each router, the received label can be associated with the next hop and a second label, for instance using a mapping table. Accordingly, when the router receives a packet, the router can match the label in the packet with one entry in the mapping table and replace the label with the second label before forwarding the packet to the next hop.
Further, some routing protocols, such as Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS), can currently support Multi-Topology (MT) routing. Using MT routing, the packets corresponding to different network topologies, which comprise nodes and links that communicate based on different architectures and/or signaling mechanisms, can be routed separately in the network. Additionally, different level of services can be assigned to different network topologies, such as level of security or quality of service (QoS), which simplifies network management and/or operations. However, MT routing is not currently supported in MPLS networks.